Announcing the release of a new R package ResistorArray.
This package solves the (nontrivial) general problem of resistance on
arbitrary (finite)
resistor arrays.
Outside electrical engineering, the problem has a wide range of
applications to
situations such as groundwater modelling; there is a direct
correspondence
between electrical networks and random walks.
The package has a reasonably complete set of literature references, and
solves a number
of classical problems such as the resistance between opposite points of
a skeleton resistor
cube, and the Wheatstone bridge.
The package comes with a variety of standard resistor arrays, including
all five platonic
solids, the Fibonacci ladder, and "N" arbitrary resistors in series.
The package gives nice numerical illustrations of a few theoretical
results from the
recent (2004) literature.
One of the Google aptitude tests was to determine the electrical
resistance between two points
on an infinite grid of resistors. I couldn't solve this problem
analytically (although I found the
other day that a solution does exist); ResistorArray gets the answer
correct to within about 1%.
--
Robin Hankin
Uncertainty Analyst
Southampton Oceanography Centre
European Way, Southampton SO14 3ZH, UK
tel 023-8059-7743